CYTOPLASMIC INCLUSIONS 137 



ophthirms has none at all at any time in its life cycle (MacLennan, 

 1936), and the function of synthesis and storage of the protein re- 

 serves is taken over by the macronucleus. 



The composition of the segregation granules of Protozoa other than 

 Opalina is known only in the case of the refractive bodies and blebs 

 of Amoeba. The osmiophilic shell of the refractive bodies of Amoeba 

 has a protein stroma impregnated with a lipid substance (Mast and 

 Doyle, 1935a). This portion stains with Sudan III only after Ciaccio's 

 method for "unmasking" the lipoids, and is intensely blue in Nile blue. 

 These granules are not dissolved in alcohol in twelve hours, but they 

 do lose their positive reaction to fat soluble dyes. They respond to the 

 methylene-blue-sulphuric test for metachromatin and give a faint re- 

 action with Millon's reagent. Within this layer a brittle carbohydrate 

 shell and an unknown fluid are found. The stainable blebs on crystals 

 in the same protozoan, when first formed, contain only lipoids, but as 

 they grow larger, protein is added so that their final composition is 

 similar to the shell of the refractive bodies of the cytoplasm. These 

 granules are therefore quite different from the segregation granules of 

 Opalina, since Kedrowsky showed that whatever else might be stored 

 in these bodies, they do not segregate lipoids. However, since the re- 

 fractive bodies do segregate proteins and stain with neutral red, they 

 are included as segregation bodies. This is, of course, arbitrary, since 

 they overlap on the Golgi granules and on the reserve granules. Suffi- 

 cient mineral ash is present to mark the vacuome in incinerated speci- 

 mens of Opalina (Horning and Scott, 1933) and Paramecium (Mac- 

 Lennan and Murer, 1934). The only striking fact about the segregation 

 bodies in most Protozoa is that with the exception of those in Opalina and 

 Amoeba, not even a sketchy outline of their composition is available. 



The function, in so far as it is known, agrees closely with the storage 

 function described for the granules in Opalina. Variations of the num- 

 bers of the segregation granules have been found in Paramecium (Duni- 

 hue, 1931) and in Vorticella (Finley, 1934). Dunihue was able to 

 correlate the decrease in numbers with starvation, thus indicating a 

 storage function. Mast and Doyle (1935a) showed that both protein and 

 lipoid materials are found in the blebs on the crystals and on the re- 

 fractive bodies. Since the blebs appear shortly after feeding and since 

 they in turn disappear as the refractive bodies are increasing, the blebs 



